The catecholamine (dopamine and noradrenaline) innervation of the hypothalamus will be analyzed in the rat and monkey using the glyoxylic acid fluorescence histochemical method. The ontogeny of the noradrenaline neuron innervation of the hippocampal formation and neocortex will be analyzed using biochemical uptake studies and the glyoxylic acid method. The effect of a specific neurotoxin, 6-hydroxydopamine, on the development of noradrenaline neurons will be studied morphologically using the glyoxylic acid method. BIBLIOGRAPHIC REFERENCES: Kromer, L. and Moore, R.Y. Cochlear nucleus innervation by central norepinephrine neurons in the rat. Brain Research 118: 531-577, 1977. Sipe, J.C. and Moore, R.Y. The lateral hypothalamic area: An ultrastructural analysis. Cell and Tissue Research 179: 177-196, 1977.